The invention relates to a ring network for communication between one chip processors each having a serial transmitter and a serial receiver.
In general, there are three different types of granting transmission privilege at a network. ETHERNET uses the so-called CSMA/CD method, (carrier sense multiple access with colision detection). All processors have equal priority. ARCNET uses the so-called token passing method where transmission privilege is transferred from one processor to the next and upon loss of transmission privilege a complicated procedure is necessary to newly determine active processors. The IBM ring has data circulate in a ring and transmission privilege is transferred according to the token passing method. The known local networks and their modifications need for coupling a one chip processor at least a network controller, a line driver and sometimes a code converter and a Fifo-intermediate memory as additional IC-units. In my German Offenlegungsschriften Nos. 3313240 and 3333847 and in my U.S. patent application Ser. No. 649,372 filed on Nov. 9, 1984, I have disclosed a local network operating according to the CSMA/CD method and needing for coupling to the network a line-driver only as an additional IC-unit. The one chip processors may operate independently as a local processor and interrupt controlled as a network controller.